As the National Institutes of Health reports the final results of the Roadmap Epigenomics Mapping Consortium – an initiative to produce a public resource of mapped human epigenomes to catalyze basic biology and disease-oriented research --– in a series of companion papers, Baylor College of Medicine researchers reported their role in directing the Data Analysis and Coordination Center of the project in the journals Nature and Nature Communications online today.

The epigenome refers to the totality of epigenetic information within each human cell. Such information is encoded in the form of chemical modifications of DNA and associated proteins.

“Unlike the genome, which is shared by almost all the cells in our body, epigenomes code for cellular properties that distinguish one cell type from another,” said Dr. Aleksandar Milosavljevic, professor of molecular and human genetics at Baylor and principal investigator on the Baylor project site. “Cells acquire epigenomes during development. In a computer analogy, genome is the ‘firmware’ of a cell while epigenome is the ‘software’ that specifies how any specific cell within a human body functions. Because of their plasticity, epigenomes contain footprints of environmental influences during a human lifetime, thus opening the door to understanding the role environment plays in human diseases.”

The NIH Roadmap Epigenomics publications reported today in Nature journals provide analysis of epigenomes across the diversity of human cell types, thus providing the first comprehensive perspective on the role of the epigenome in human health and disease, Milosavljevic said.

The Epigenome Center at Baylor, directed by Milosavljevic, served as the Data Analysis and Coordination Center for the project.

The Baylor team performed the analysis of epigenetic programs of long intergenic non-coding RNA (lincRNA) genes, the most numerous class of non-protein coding genes in humans.

The team assigned cell-type specific role to a majority (69 percent) of lincRNAs, thus providing a "guidebook" to interpret human genetic variation in the context of new “precision medicine” initiatives, Milosavljevic said.

Together, the reported results mark the transition from a "trailblazing" stage of epigenome research to the next, more mature stage where the full human health benefits will be realized, he said.

Funding for this work was supported by the National Institutes of Health (U01 DA025956).

Overall, the NIH Roadmap Epigenomics project involved more than 50 US institutions. The project also served as the founding member of the International Human Epigenomics Consortium (IHEC) that now involves over thirty countries and aims to bring the total number of mapped epigenomes from the current 127 to over 1000.